Web slitter



P 1969 N. w. WILSON 3,467,333

WEB SLITTER Filed Sept. 22, 1967 INVENTOR NATHAN W. WILSON ATTORNEYUnited States Patent 3,467,333 WEB SLITTER Nathan W. Wilson,Circleville, Ohio, assignor to E. I. du Pont deNemours and Company,Wilmington, Del., a corporation of Delaware Filed Sept. 22, 1967, Ser.No. 669,818 Int. Cl. B65h 35/02, 17/08 US. Cl. 242-56.2 3 ClaimsABSTRACT OF THE DISCLOSURE Web slitting apparatus having a pivoted armto position wind-up cores, and including a gas filled resilientcontainer bearing on the pivoted arm, for high speed operation andefficient start-up.

Related art This invention is an improvement of the web slitting andwinding apparatus of the type described in Nicholson, United StatesPatent No. 2,777,644 issued Jan. 15, 1957.

Background The formation of good rolls when a multiplicity of narrowstrips of thin web, such as film, paper or fabric, are wound onindividual rolls is dependent on the character of the material and onthe nature of the winding arrangement. The slitting and winding of afilm on a pivoted arm slitter of the Nicholson invention can be operatedat speeds of to 200 to 400 or more feet per minute. At the higher speedsthe pivoted arms winding in contact with the pull roll tend to bounce onthe roll, leading to poor windup pattern of the slit roll.

There have been attempts to improve the winding performance of theslitter apparatus. In US. 3,122,335 it is proposed to use a fluidcharged piston on each wind roll. The piston system is subject tooscillation at critical speeds dependent upon arm and pistonconstruction. Other systems are shown in US. 3,198,453 and in US.2,872,126.

Summary of invention In the present invention, web slitting machine ofthe Nicholson type is improved by including therewith a gas filledresilient container cooperating with the positioning pivoted arms. In aspecific embodiment the invention comprises a web slitting machinehaving a web supply, means for slitting continuous web into a pluralityof strips, a positively driven web driving roll over which the stripspass, and cores in peripheral rotating contact with the web drivingrolls and upon which the strips are wound, and pivoted arms positioningthe cores in substantially parallel relationship in peripheral contactwith the driving roll and a gas filled resilient container cooperatingwith the pivoted arm and urging the cores in contact with the webdriving roll.

The gas filled device of the invention achieves an improvement in rollformation by minimizing arm bounce by damping the oscillations whichoccur, resulting in slit rolls with a smooth windup pattern and Withoutunwanted beading. Furthermore and of considerable importance, the devicecan be readily deflated and re-inflated to permit rapid set-ups.

The invention will be more clearly understood by reference to theaccompanying drawing wherein:

FIGURE 1 is a simplified schematic drawing of a slitting apparatusemploying a device of the present invention; and

FIGURE 2 is a view of a gas filled hold-down device of the presentinvention as it bears on a pivot arm of the apparatus.

Patented Sept. 16, 1969 ice Referring to FIGURE 1, a continuous web 11,e.g., a thermoplastic film such as polyethylene terephthalate, isunwound from a supply roll 12 and thereafter is slit by knife 13,positioned between supporting rolls 14 and 15, and then passes over thesurface of main web driving drum or roll 16. At web driving roll 16 theweb, having been ,slit into a plurality of narrow strips, is wound asshown upon core 17 which is mounted at the free end of the pivot arm 18.Pivot arm 18, suspended to rotate freely about axis 19, has gas-filledhold-down device 20 to urge the windup roll 21 into uniform surfacecontact'with driving roll 16. A back-up plate 22 is provided to mountand support the hold-down device 20. The next adjacent strip of web iswound upon core 17 mounted at the free end of pivot arm 18, and so onsubstantially identical to the apparatus already described. That is,eachstrip is individually wound on a separate core disposed on theperiphery, alternatively in two or more rows parallel to the axis ofdriving roll 16.

It 'should be understood that the rolls are driven, directly or throughanother driven roll, at speeds adapted to maintain the film or web undertension. Hence as rolls of wound material increase in diameter, speed ofrotationis adjusted in the usual fashion to maintain the desired surfacespeed and, therefore, the designed film tension for good roll formation.

FIGURE 1 illustrates a general type of slitting apparatus wherein thepresent invention is highly useful but it is understood that the presentinvention can be employed in any type of slitting apparatus wherein theslit ends of the web or film are ultimately conducted onto a roll orrolls of the type illustrated in FIGURE 1.

Still with reference to FIGURE 1, the free end of pivot arm 18 isprovided with a short shaft or a mandrel upon which is mounted arotatable chuck for rigidly mounting thereon core 17. The core 17 can beof cardboard, wood, metal, plastic, etc., and is in rotating contactwith the surface of driving roll 16. Core 17 may, if desired, bepositively driven in a direction so as to maintain tension of a desireddegree upon the roll which forms on this core. It should be understoodthat the present web winding apparatus is not restricted with respect tothe number of individual winding positions which are located inperipheral contact with driving roll 16 of FIGURE 1. Usually, asindicated hereinbefore, additional rolls parallel to roll 21 on core 17are positioned alternately on an are about driving roll 16 so as toprovide proper clearance for free motion of pivot arm 18 and winding ofroll 31 on core 17.

FIGURE 2 illustrates in somewhat greater detail the gas filled resilienthold-down device of the present invention and its cooperation with thepivoted arm of the rewinder in contact with driving roll 16. This figureillustrates the device in a preferred embodiment, but modificationtherefrom can be made to conform to individual requirements.

Shown in FIGURE 2 is rigid support plate 22 to which the device 20 isfixedly clamped, as by suitably shaped flanges on the plate 22 and arigid top portion 26 on the gas bag or device 20. Plate 22 can beattached to the machine frame (not shown) or other location adapted tocause the device 20 to exert force against pivot arm 18.

The gas filled resilient container 20 can suitably be made of a thinwall reinforced elastomer tube which, of course, is sealed to be gasimpervious. For example, the container or bag can be made from a l-ply,fabricreinforced, cured, natural rubber about 60 mils thick. In use,such a bag is inflated to 2 to 10 p.s.i. gauge. A rigid tread top 26 andbottom 24 (FIG. 2) integral to the container 20 make it easy to attachto the support plate 22 and to avoid contact wear of the container 20 asit bears on the pivot arm. An elastomer with a Shore A durometerhardness of 45-50 is suitable for the treads. A tread of A to /2 inchthickness and A to 2 inches wide will function well with a pivot arm.The hold-down device is preferably of a size to extend the full lengthof the wind roll. Consequently, when the pivot arms must be reset todifferent widths, the adjustments can be made rapidly and easily asfollows: the pressure is released from the device 20 through a gasconduit 23. The arm is moved and set. Then the container is repressuredthrough conduit 23 from a gas source, e.g. a compressor.

The give or yield required of the resilient container 20 will dependupon the location on the arm. A yield of 1 to 3 inches has been foundsatisfactory for rolls up to 12 inches in diameter and 6 inches wide.The gas or inflatant employed can be any permanent gas such as air,nitrogen, or carbon dioxide.

In operation, the hold-down device 20 presses again the pivot arm 18. Asthe windup roll 21 increases in diameter after taking up web or filmfrom driving roll 16, the pivot arm 18 compresses the container 20 whichthereby maintains pressure on the pivot arm, damping oscillations causedby arm bounce.

When the improved slitting machine of this invention is used, theslitter may be operated at 600 or more feet per minute. The increase ofa factor of 2 or more in speed is achieved without loss in yield becauseof uneven windup edge.

From the foregoing discussion and description, it is evident that thepresent discovery is an important improvement in web slitting andwinding machines. The improvement efiectively overcomes arm bounce withits attendant effects on rolls produced, and has the further advantageof simplicity in allowing speedy adjustments and set-ups of theequipment. While it has been described with certain details, it shouldbe evident that changes can be made without departing from its scope.

What is claimed is:

1. In a web slitting machine having a web supply from which a continuousweb is fed, means for slitting the continuous web into a plurality ofcontinuous strips, a positively driven web driving roll over which thestrips pass, and cores in peripheral rotating contact with the webdriving roll and upon which the strips are wound, and pivoted armspositioning said cores in substantially parallel relationship and inperipheral contact with the web driving roll, the improvement comprisinggas filled resilient container including a tread attached to its surfacecooperating with the pivoted arm and urging the cores in contact withthe web driving roll.

2. A web slitting machine according to claim 1 including means to filland exhaust gas from said container to facilitate ready start-up of theslitting machine.

3. A web slitting machine according to claim 1 in which the gascontainer is formed of gas impervious fabric-reinforced rubber.

References Cited UNITED STATES PATENTS 3,222,004 12/1965 Crowe 242-562 X3,237,877 3/ 1966 Printz et a1. 242-66 WILLIAM S. BURDEN, PrimaryExaminer U.S. Cl. X.R.

